Skip to main content

Full text of "Practical Organic Chemistry"

p-CIILOROTOLUENE

solution is gradually added. The clear solution is then gently
warmed on the water-bath until the evolution of nitrogen ceases.
The solution, which has become very dark coloured, is distilled
in steam until the distillate produces only a slight precipitate
with bromine water (500 c.c.). A small quantity of tarry residue
remains. The distillate is then extracted three times with small
quantities (50 c.c.) of ether. The ethereal solution is dehydrated
over anhydrous sodium sulphate, filtered, and the ether removed
on the water-bath. Thc/-cresol is then distilled over the flame
with a condenser tube, and collected at 195—200°. The distil-
late, which has a yellow colour, solidifies on cooling. Yield 10
— 15 grams.

4-2N2~KNa,S(),,~h211/3.
Properties.— Colourless crystals ; in. p. 36° ; b. p. 202°.
Reactions.—Make a solution of //-crcsol by shaking up a
few drops with 5 c.c. of water. To one portion add a few drops
of bromine water. A white precipitate of tetrabromocrcsol
is formed. To another portion add a drop of ferric chloride.
A blue colouration is produced. See Appendix^ p. 284.
PREPARATION 65.
p-Chlorotoluene,    CnH.l</£1H-<» l
Sandmcyer, Tfcr., 18(84, 17, 2651 ; Wynne, Trans. Chcm. Soc.,
1892,61,1072.
50 grins./-toluicline.
120 c.c. cone, hydrochloric acid (in So c.c. water),
40 grins, sodium nitrite (coarsely powdered).
30    „      copper carbonate to be dissolved in 300 c.c. cone.
hydrochloric acid
Dissolve the /-toluidine in the hydrochloric acid and then
cool, quickly in a beaker, and stir so as to obtain small crystals.
Place the beaker in ice and salt and, whilst it is cooling,
prepare a solution of cuprous chloride. Dissolve the copper
carbonate in the hydrochloric arid, and boil with excess of
copper turnings until a nearly colourless solution is obtained.
The solution is decanted into a large round flask (2 litres)